On 8/14/24 3:17 PM, Eduard Zingerman wrote:
On Tue, 2024-08-13 at 11:49 -0700, Martin KaFai Lau wrote:
From: Martin KaFai Lau <martin.lau@xxxxxxxxxx>
The existing prologue has been able to call bpf helper but not a kfunc.
This patch allows the prologue/epilogue to call the kfunc.
[...]
Once the insn->off is determined (either reuse an existing one
or an unused one is found), it will call the existing add_kfunc_call()
and everything else should fall through.
Signed-off-by: Martin KaFai Lau <martin.lau@xxxxxxxxxx>
---
fwiw, don't see any obvious problems with this patch.
Reviewed-by: Eduard Zingerman <eddyz87@xxxxxxxxx>
kernel/bpf/verifier.c | 116 ++++++++++++++++++++++++++++++++++++++++--
1 file changed, 113 insertions(+), 3 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 5e995b7884fb..2873e1083402 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2787,6 +2787,61 @@ static struct btf *find_kfunc_desc_btf(struct bpf_verifier_env *env, s16 offset)
return btf_vmlinux ?: ERR_PTR(-ENOENT);
}
+static int find_kfunc_desc_btf_offset(struct bpf_verifier_env *env, struct btf *btf,
+ struct module *module, s16 *offset)
+{
+ struct bpf_kfunc_btf_tab *tab;
+ struct bpf_kfunc_btf *b;
+ s16 new_offset = S16_MAX;
+ u32 i;
+
+ if (btf_is_vmlinux(btf)) {
+ *offset = 0;
+ return 0;
+ }
+
+ tab = env->prog->aux->kfunc_btf_tab;
+ if (!tab) {
+ tab = kzalloc(sizeof(*tab), GFP_KERNEL);
+ if (!tab)
+ return -ENOMEM;
+ env->prog->aux->kfunc_btf_tab = tab;
+ }
+
+ b = tab->descs;
+ for (i = tab->nr_descs; i > 0; i--) {
Question: why iterating in reverse here?
Agreed. It is unnecessary. I will change it to iterate forward in the next re-spin.
Thanks for the review!
